Yes, Bowser Jr.
You unlock him by winning the 100cc leaf cup! =-)
win the 100cc mushroom cup and flower cup
You can get karts by unlocking them throughout the game, and you can unlock racing clothing (if your using your Mii), You can unlock characters, by winning the 50cc, 100cc, 150cc, and also 150cc mirror cups.
Just keep playing the grand prix until you unlock something. I've memorized a few unlocking formulas, so here they are:To unlock the Star Cup: Get at least 3rd place or betterin the Mushroom and Flower Cup.To unlock Dry Bones: Unlock the 100cc Leaf Cup.To unlock Daisy: Win the 150cc Special Cup. (Win the Star Cup 150cc to win the Special Cup 150cc)To unlock the Leaf Cup: Win the 100cc Banana Cup.To unlock the Lightning Cup: Win the 100cc Leaf Cup.That's all I know for now. I hope this answered your question! :)
i am not reallysure, but if you get a star rank in all the retro 100cc cups, you unlock Bowser Jr.
Rob the Robot
Well you can get mii costume A (Normal Looking) or B (girls costume). You can unlock Costume A by beating 100cc Special cup, B... well you have to beat all the 32 staff ghost by 7 seconds... Which none can do.
you play the star cup 100cc and finish in the top 5 for points
In order to unlock the Star Cup in 100cc, you must first beat the 100cc Mushroom and Flower cups.
By winning gold in all the cups, so the 50cc, 100cc, 150cc and 150ccMirror(unlock this one by getting at least one star in the other cups)
defeat 100cc star cup which also unlocks 100cc special-beat to get mii outfit a
Beat 100cc retro cups with 1 star or better.